AIR303: Add rule for deprecated task_concurrency parameter

- Add new rule to detect deprecated task_concurrency parameter
- Update documentation and tests
- Add snapshot tests

crates/ruff_linter/resources/test/fixtures/airflow/AIR303.py

@@ -0,0 +1,23 @@
+from airflow.operators.python import PythonOperator
+from airflow import DAG
+
+# Using deprecated task_concurrency parameter
+task1 = PythonOperator(
+    task_id="task1",
+    task_concurrency=2,  # This should trigger AIR303
+    python_callable=lambda: None,
+)
+
+# Using new max_active_tis_per_dag parameter
+task2 = PythonOperator(
+    task_id="task2",
+    max_active_tis_per_dag=2,  # This should be fine
+    python_callable=lambda: None,
+)
+
+# Another example with task_concurrency
+task3 = PythonOperator(
+    task_id="task3",
+    task_concurrency=5,  # This should trigger AIR303
+    python_callable=lambda: None,
+)

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -1076,6 +1076,9 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
             if checker.enabled(Rule::AirflowDagNoScheduleArgument) {
                 airflow::rules::dag_no_schedule_argument(checker, expr);
             }
+            if checker.enabled(Rule::AirflowDeprecatedTaskConcurrency) {
+                airflow::rules::task_concurrency_check(checker, expr);
+            }
         }
         Expr::Dict(dict) => {
             if checker.any_enabled(&[

crates/ruff_linter/src/codes.rs

@@ -1035,6 +1035,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         // airflow
         (Airflow, "001") => (RuleGroup::Stable, rules::airflow::rules::AirflowVariableNameTaskIdMismatch),
         (Airflow, "301") => (RuleGroup::Preview, rules::airflow::rules::AirflowDagNoScheduleArgument),
+        (Airflow, "303") => (RuleGroup::Preview, rules::airflow::rules::AirflowDeprecatedTaskConcurrency),
 
         // perflint
         (Perflint, "101") => (RuleGroup::Stable, rules::perflint::rules::UnnecessaryListCast),

crates/ruff_linter/src/rules/airflow/mod.rs

@@ -14,6 +14,7 @@ mod tests {
 
     #[test_case(Rule::AirflowVariableNameTaskIdMismatch, Path::new("AIR001.py"))]
     #[test_case(Rule::AirflowDagNoScheduleArgument, Path::new("AIR301.py"))]
+    #[test_case(Rule::AirflowDeprecatedTaskConcurrency, Path::new("AIR303.py"))]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());
         let diagnostics = test_path(

crates/ruff_linter/src/rules/airflow/rules/mod.rs

@@ -1,5 +1,7 @@
 pub(crate) use dag_schedule_argument::*;
+pub(crate) use task_concurrency::*;
 pub(crate) use task_variable_name::*;
 
 mod dag_schedule_argument;
+mod task_concurrency;
 mod task_variable_name;

crates/ruff_linter/src/rules/airflow/rules/task_concurrency.rs

@@ -0,0 +1,75 @@
+use ruff_diagnostics::{Diagnostic, Violation};
+use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast as ast;
+use ruff_python_ast::Expr;
+use ruff_python_semantic::Modules;
+use ruff_text_size::Ranged;
+
+use crate::checkers::ast::Checker;
+
+/// ## What it does
+/// Checks for usage of the deprecated `task_concurrency` parameter in Airflow Operators.
+///
+/// ## Why is this bad?
+/// The `task_concurrency` parameter has been deprecated and renamed to `max_active_tis_per_dag`
+/// in Airflow 3.0. Code using the old parameter name needs to be updated to ensure
+/// compatibility with Airflow 3.0.
+///
+/// ## Example
+/// ```python
+/// from airflow.operators.python import PythonOperator
+///
+/// # Invalid: using deprecated parameter
+/// task = PythonOperator(task_id="my_task", task_concurrency=2)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from airflow.operators.python import PythonOperator
+///
+/// # Valid: using new parameter name
+/// task = PythonOperator(task_id="my_task", max_active_tis_per_dag=2)
+/// ```
+#[violation]
+pub struct AirflowDeprecatedTaskConcurrency {
+    pub old_param: String,
+    pub new_param: String,
+}
+
+impl Violation for AirflowDeprecatedTaskConcurrency {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        let AirflowDeprecatedTaskConcurrency {
+            old_param,
+            new_param,
+        } = self;
+        format!("Use `{new_param}` instead of deprecated `{old_param}` parameter")
+    }
+}
+
+/// AIR303
+pub(crate) fn task_concurrency_check(checker: &mut Checker, value: &Expr) {
+    // If the value is not a call, we can't do anything.
+    let Expr::Call(ast::ExprCall {
+        func: _, arguments, ..
+    }) = value
+    else {
+        return;
+    };
+
+    // If we haven't seen any airflow imports, we can't do anything.
+    if !checker.semantic().seen_module(Modules::AIRFLOW) {
+        return;
+    }
+
+    // Check for the deprecated parameter
+    if let Some(keyword) = arguments.find_keyword("task_concurrency") {
+        checker.diagnostics.push(Diagnostic::new(
+            AirflowDeprecatedTaskConcurrency {
+                old_param: "task_concurrency".to_string(),
+                new_param: "max_active_tis_per_dag".to_string(),
+            },
+            keyword.range(),
+        ));
+    }
+}

crates/ruff_linter/src/rules/airflow/snapshots/ruff_linter__rules__airflow__tests__AIR303_AIR303.py.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff_linter/src/rules/airflow/mod.rs
+snapshot_kind: text
+---
+AIR303.py:7:5: AIR303 Use `max_active_tis_per_dag` instead of deprecated `task_concurrency` parameter
+  |
+5 | task1 = PythonOperator(
+6 |     task_id="task1",
+7 |     task_concurrency=2,  # This should trigger AIR303
+  |     ^^^^^^^^^^^^^^^^^^ AIR303
+8 |     python_callable=lambda: None,
+9 | )
+  |
+
+AIR303.py:21:5: AIR303 Use `max_active_tis_per_dag` instead of deprecated `task_concurrency` parameter
+   |
+19 | task3 = PythonOperator(
+20 |     task_id="task3",
+21 |     task_concurrency=5,  # This should trigger AIR303
+   |     ^^^^^^^^^^^^^^^^^^ AIR303
+22 |     python_callable=lambda: None,
+23 | )
+   |